Radio capability change

ABSTRACT

Apparatuses, methods, and systems are disclosed for modifying a radio capability. One method includes determining that an update of a radio access capability for a first radio access technology is required based at least in part on whether to use a second radio access technology. The method includes switching to an idle state based on determining that the update of the radio access capability for the first radio access technology is required and transmitting a request message indicating that the update of the radio access capability for the first radio access technology is required in response to switching to the idle state, the request message further indicating to delete a stored radio access capability associated with the UE and obtain a new radio access capability associated with the UE.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. patent application Ser. No.16/417,155 entitled “RADIO CAPABILITY CHANGE” and filed on May 20, 2019for Genadi Velev, Prateek Basu Mallick, Joachim Loehr, and RaviKuchibhotla, which application is incorporated herein by reference.Application Ser. No. 16/417,155 claims priority to U.S. ProvisionalPatent Application No. 62/673,790 entitled “RADIO CAPABILITYMODIFICATION FOR DUAL REGISTRATION TERMINALS” and filed on May 18, 2018for Genadi Velev, Prateek Basu Mallick, Joachim Loehr, and RaviKuchibhotla, which application is incorporated herein by reference.

FIELD

The subject matter disclosed herein relates generally to wirelesscommunications and more particularly relates to radio capability change.

BACKGROUND

In certain wireless communications networks, an evolved packet corenetwork (“EPC”) and a fifth generation core network (“5GC”) may bedeployed without an N26 interface. The N26 interface supports EPS/5GSinterworking, thus a User Equipment (“UE”) may simultaneously registerwith a evolved packet system (“EPS”) and a fifth-generation system(“5GS”), referred to as Dual Registration (“DR”) mode for interworkingbetween EPS/E-UTRAN and 5GS/NR. However, when a UE operating in DR modegoes out of 5GS/NR coverage and enters an Evolved UMTS Terrestrial RadioAccess (“E-UTRA”) cell providing access to both EPC and 5GC, continuingDR mode would undesirably result in the UE: A) using the same cell toconnect to two different CNs and B) having two Radio Resource Control(“RRC”) connections to the same Evolved Node B (“eNB”), whereas the oneRRC connection is for EPC and the other one to 5GC.

BRIEF SUMMARY

Methods are disclosed for modifying a radio capability. Apparatuses andsystems also perform the functions of the methods. The methods may alsobe embodied in one or more computer program products comprisingexecutable code.

A method for modifying a radio capability includes determining that anupdate of a radio access capability for a first radio access technologyis required based at least in part on whether to use a second radioaccess technology and switching to an idle state based on determiningthat the update of the radio access capability for the first radioaccess technology is required. The method includes transmitting arequest message indicating that the update of the radio accesscapability for the first radio access technology is required in responseto switching to the idle state, the request message further indicatingto delete a stored radio access capability associated with the UE andobtain a new radio access capability associated with the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described abovewill be rendered by reference to specific embodiments that areillustrated in the appended drawings. Understanding that these drawingsdepict only some embodiments and are not therefore to be considered tobe limiting of scope, the embodiments will be described and explainedwith additional specificity and detail through the use of theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram illustrating one embodiment of awireless communication system for modifying a radio capability;

FIG. 2 is a block diagram illustrating one embodiment of a networkarchitecture for modifying a radio capability;

FIG. 3A is a block diagram illustrating one procedure for modifying aradio capability;

FIG. 3B is a continuation of FIG. 3A;

FIG. 4 is a block diagram illustrating another procedure for modifying aradio capability;

FIG. 5 is a block diagram illustrating a user equipment apparatus formodifying a radio capability;

FIG. 6 is a flow chart diagram illustrating one method of modifying aradio capability; and

FIG. 7 is a flow chart diagram illustrating another method of modifyinga radio capability.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of theembodiments may be embodied as a system, apparatus, method, or programproduct. Accordingly, embodiments may take the form of an entirelyhardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,embodiments may take the form of a program product embodied in one ormore computer readable storage devices storing machine readable code,computer readable code, and/or program code, referred hereafter as code.The storage devices may be tangible, non-transitory, and/ornon-transmission. The storage devices may not embody signals. In acertain embodiment, the storage devices only employ signals foraccessing code.

Any combination of one or more computer readable medium may be utilized.The computer readable medium may be a computer readable storage medium.The computer readable storage medium may be a storage device storing thecode. The storage device may be, for example, but not limited to, anelectronic, magnetic, optical, electromagnetic, infrared, holographic,micromechanical, or semiconductor system, apparatus, or device, or anysuitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage devicewould include the following: an electrical connection having one or morewires, a portable computer diskette, a hard disk, a random-access memory(“RAM”), a read-only memory (“ROM”), an erasable programmable read-onlymemory (“EPROM” or Flash memory), a portable compact disc read-onlymemory (“CD-ROM”), an optical storage device, a magnetic storage device,or any suitable combination of the foregoing. In the context of thisdocument, a computer readable storage medium may be any tangible mediumthat can contain, or store a program for use by or in connection with aninstruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number oflines and may be written in any combination of one or more programminglanguages including an object-oriented programming language such asPython, Ruby, Java, Smalltalk, C++, or the like, and conventionalprocedural programming languages, such as the “C” programming language,or the like, and/or machine languages such as assembly languages. Thecode may execute entirely on the user's computer, partly on the user'scomputer, as a stand-alone software package, partly on the user'scomputer and partly on a remote computer or entirely on the remotecomputer or server. In the latter scenario, the remote computer may beconnected to the user's computer through any type of network, includinga local area network (“LAN”) or a wide area network (“WAN”), or theconnection may be made to an external computer (for example, through theInternet using an Internet Service Provider).

Reference throughout this specification to “one embodiment,” “anembodiment,” or similar language means that a particular feature,structure, or characteristic described in connection with the embodimentis included in at least one embodiment. Thus, appearances of the phrases“in one embodiment,” “in an embodiment,” and similar language throughoutthis specification may, but do not necessarily, all refer to the sameembodiment, but mean “one or more but not all embodiments” unlessexpressly specified otherwise. The terms “including,” “comprising,”“having,” and variations thereof mean “including but not limited to,”unless expressly specified otherwise. An enumerated listing of itemsdoes not imply that any or all of the items are mutually exclusive,unless expressly specified otherwise. The terms “a,” “an,” and “the”also refer to “one or more” unless expressly specified otherwise.

Furthermore, the described features, structures, or characteristics ofthe embodiments may be combined in any suitable manner. In the followingdescription, numerous specific details are provided, such as examples ofprogramming, software modules, user selections, network transactions,database queries, database structures, hardware modules, hardwarecircuits, hardware chips, etc., to provide a thorough understanding ofembodiments. One skilled in the relevant art will recognize, however,that embodiments may be practiced without one or more of the specificdetails, or with other methods, components, materials, and so forth. Inother instances, well-known structures, materials, or operations are notshown or described in detail to avoid obscuring aspects of anembodiment.

Aspects of the embodiments are described below with reference toschematic flowchart diagrams and/or schematic block diagrams of methods,apparatuses, systems, and program products according to embodiments. Itwill be understood that each block of the schematic flowchart diagramsand/or schematic block diagrams, and combinations of blocks in theschematic flowchart diagrams and/or schematic block diagrams, can beimplemented by code. The code may be provided to a processor of ageneral-purpose computer, special purpose computer, or otherprogrammable data processing apparatus to produce a machine, such thatthe instructions, which execute via the processor of the computer orother programmable data processing apparatus, create means forimplementing the functions/acts specified in the schematic flowchartdiagrams and/or schematic block diagrams block or blocks.

The code may also be stored in a storage device that can direct acomputer, other programmable data processing apparatus, or other devicesto function in a particular manner, such that the instructions stored inthe storage device produce an article of manufacture includinginstructions which implement the function/act specified in the schematicflowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable dataprocessing apparatus, or other devices to cause a series of operationalsteps to be performed on the computer, other programmable apparatus, orother devices to produce a computer implemented process such that thecode which execute on the computer or other programmable apparatusprovide processes for implementing the functions/acts specified in theflowchart and/or block diagram block or blocks.

The schematic flowchart diagrams and/or schematic block diagrams in theFigures illustrate the architecture, functionality, and operation ofpossible implementations of apparatuses, systems, methods, and programproducts according to various embodiments. In this regard, each block inthe schematic flowchart diagrams and/or schematic block diagrams mayrepresent a module, segment, or portion of code, which includes one ormore executable instructions of the code for implementing the specifiedlogical function(s).

It should also be noted that, in some alternative implementations, thefunctions noted in the block may occur out of the order noted in theFigures. For example, two blocks shown in succession may, in fact, beexecuted substantially concurrently, or the blocks may sometimes beexecuted in the reverse order, depending upon the functionalityinvolved. Other steps and methods may be conceived that are equivalentin function, logic, or effect to one or more blocks, or portionsthereof, of the illustrated Figures.

Although various arrow types and line types may be employed in theflowchart and/or block diagrams, they are understood not to limit thescope of the corresponding embodiments. Indeed, some arrows or otherconnectors may be used to indicate only the logical flow of the depictedembodiment. For instance, an arrow may indicate a waiting or monitoringperiod of unspecified duration between enumerated steps of the depictedembodiment. It will also be noted that each block of the block diagramsand/or flowchart diagrams, and combinations of blocks in the blockdiagrams and/or flowchart diagrams, can be implemented by specialpurpose hardware-based systems that perform the specified functions oracts, or combinations of special purpose hardware and code.

The description of elements in each figure may refer to elements ofproceeding figures. Like numbers refer to like elements in all figures,including alternate embodiments of like elements.

Generally, the present disclosure describes systems, methods, andapparatus for modifying a radio capability. In various embodiments, a UEmay operate in a Dual Registration (“DR”) mode having simultaneousregistrations with EPS and 5GS. In some embodiments, the DR mode is usedonly in networks which do not support interworking via N26 interface.

In a given public land mobile network (“PLMN”), the Access and mobilityManagement Function (“AMF”) (in the 5GC) and the Mobility ManagementEntity (“MIME”), (in the EPC) provide an indication to UEs that EPS-5GSinterworking without N26 is supported. This indication may be providedduring Initial Registration (in 5GC) or during the Attach procedure (inEPC). Moreover, this indication is valid for the entire Registered PLMNand for PLMNs equivalent to the Registered PLMN. Additionally, the sameindication is provided to all UEs served by the same PLMN.

Accordingly, UEs that operate in a PLMN that supports EPS-5GSinterworking without N26 (e.g., operable in DR mode) may use thisindication to decide whether to register early in the target system.Note that the network does not provide mapped Quality of Service (“QoS”)parameters to a UE in DR mode, i.e., if interworking with N26 is notsupported.

In various embodiments, the UE provides the following indications to thecore network (e.g., AMF or MME) during Initial Attach to EPC or duringRegistration to 5GC:

In some embodiments, the UE indicates its support of EPC Non-AccessStratum (“NAS”) during the registration procedure with the AMF or itssupport of 5GC NAS during the attach procedure with the MME. Forexample, the UE may provide the indication using the “UE NetworkCapability” parameter. This indication might be used by the AMF/MME toselect combo PGW-C+SMF node for EPS-5GS interworking.

Additionally, the UE may indicate that it supports Request Type flag“handover” for Packet Data Network (“PDN”) connectivity request duringthe attach procedure in EPC and during initial registration and mobilityRegistration Update in 5GC. Note that this indication may be used forInternet Protocol (“IP”) address preservation in the case ofinterworking without N26.

For interworking without N26, the UE needs to indicate that it is movingfrom 5GC (or from EPC) so that the MME or AMF does not include “initialattach” indicator to the Home Subscriber Server (“HSS”) and Unified DataManagement entity (“UDM”). Because the “initial attach” indicator is notincluded, the HSS+UDM does not cancel the earlier registration of AMF orMME.

FIG. 1 depicts a wireless communication system 100 for suspendingservices in a first core network while attached to a second corenetwork, according to embodiments of the disclosure. In one embodiment,the wireless communication system 100 includes at least one remote unit105, a first access network 120 containing at least one base unit 110, asecond access network 125 containing at least one base unit 110,wireless communication links 115 between remote unit 105 and base unit110, a first core network 130, and a second core network 140. Eventhough a specific number of remote units 105, access networks 120, 125,base units 110, wireless communication links 115, and core networks 130,140 are depicted in FIG. 1 , one of skill in the art will recognize thatany number of remote units 105, access networks 120, 125, base units110, wireless communication links 115, and core networks 130, 140 may beincluded in the wireless communication system 100. In variousembodiments, the access networks 120, 125 may contain one or morewireless LAN (“WLAN”) (e.g., Wi-Fi™) access points (“APs”). Here, thefirst access network 120, second access network 125, first core network130 and second core network 140 belong to the same mobile communicationnetwork (e.g., the same PLMN).

In one implementation, the wireless communication system 100 iscompliant with the 5G system and the Long Term Evolution (“LTE”) systemspecified in the Third Generation Partnership Project (“3GPP”)specifications. More generally, however, the wireless communicationsystem 100 may implement some other open or proprietary communicationnetwork, for example, Worldwide Interoperability for Microwave Access(“WiMAX”), among other networks. The present disclosure is not intendedto be limited to the implementation of any particular wirelesscommunication system architectures or protocols.

In one embodiment, the remote units 105 may include computing devices,such as desktop computers, laptop computers, personal digital assistants(“PDAs”), tablet computers, smart phones, smart televisions (e.g.,televisions connected to the Internet), smart appliances (e.g.,appliances connected to the Internet), set-top boxes, game consoles,security systems (including security cameras), vehicle on-boardcomputers, network devices (e.g., routers, switches, modems), or thelike. In some embodiments, the remote units 105 include wearabledevices, such as smart watches, fitness bands, optical head-mounteddisplays, or the like. Moreover, the remote units 105 may be referred toas subscriber units, mobiles, mobile stations, users, terminals, mobileterminals, fixed terminals, subscriber stations, UEs, user terminals, adevice, or by other terminology used in the art. The remote units 105may communicate directly with one or more of the base units 110 viauplink (“UL”) and downlink (“DL”) communication signals. Furthermore,the UL and DL communication signals may be carried over the wirelesscommunication links 115.

In some embodiments, the remote units 105 communicate with a remote host180 (for example, an application server) via a data path that passesthrough one of the core networks 130, 140 and through the data network175. For example, a remote unit 105 may establish a Protocol Data Unit(“PDU”) session (or similar data connection) to the data network 175 viathe first core network 130. The first core network 130 then relaystraffic between the remote unit 105 and the remote host 180 using thePDU session. As another example, a remote unit 105 may establish a PDNconnection to the data network 175 via the second core network 140. Thesecond core network 140 then relays traffic between the remote unit 105and the remote host 180 using the PDN connection.

The base units 110 may be distributed over a geographic region. Incertain embodiments, a base unit 110 may also be referred to as anaccess terminal, an access point, a base, a base station, a Node-B, aneNB, a Next Generation Node B (“gNB”), a Home Node-B, a relay node, adevice, or by any other terminology used in the art. The base units 110are generally part of a radio access network (“RAN”), such as the firstaccess network 120 (e.g., NG-RAN) and/or the second access network 125(e.g., Evolved UMTS Terrestrial Radio Access Network (“E-UTRAN”)), thatmay include one or more controllers communicably coupled to one or morecorresponding base units 110. These and other elements of the radioaccess network are not illustrated, but are well known generally bythose having ordinary skill in the art.

The base units 110 may serve a number of remote units 105 within aserving area, for example, a cell or a cell sector via a wirelesscommunication link 115. The base units 110 may communicate directly withone or more of the remote units 105 via communication signals.Generally, the base units 110 transmit downlink (“DL”) communicationsignals to serve the remote units 105 in the time, frequency, and/orspatial domain. Furthermore, the DL communication signals may be carriedover the wireless communication links 115. The wireless communicationlinks 115 may be any suitable carrier in licensed or unlicensed radiospectrum. The wireless communication links 115 facilitate communicationbetween one or more of the remote units 105 and/or one or more of thebase units 110.

As depicted, the wireless communication system 100 includes both a firstcore network 130 and a second core network 140 and various interworkingnetwork functions for to support interworking between the user plane andcertain control plane functions in the first core network 130 and thesecond core network 140. The first core network 130 includes an AMF 135that is not shared with the second core network 140. Similarly, thesecond core network 140 includes a MME 145 and a Serving Gateway (“SGW”)150 that are note shared with the first core network 130. However, thereis a combined User Plane Function (“UPF”) and Packet Data Gateway(“PGW”)-user-plane (i.e., “UPF+PGW-U”) 155, a combined SessionManagement Function (“SMF”) and PGW-control-plane (i.e., “SMF+PGW-C”)160, a combined Policy Control Function (“PCF”) and Policy and ChargingRules Function (“PCRF”) (i.e., “PCF+PCRF”) 165, and a combined HSS andUDM (i.e., “HSS+UDM”) that support interworking between the first corenetwork 130 and second core network 140. Note that the notions“SMF+PGW-C” and “UPF+PGW-U” are used to show that the network functionsused for, e.g., PDU Sessions in 5GC and PDN Connections in EPC arecommon, in case that IP session continuity is required during transferof PDU Sessions to PDN Connections and vice-versa. Although specificnumbers and types of network functions are depicted in FIG. 1 , one ofskill in the art will recognize that any number and type of networkfunctions may be included in the mobile core networks 130 and/or 140.

As depicted, the wireless communication system 100 includes variousnetwork interfaces that facilitate communication among the core network(“CN”) elements. For example, a base unit 110 (or RAN) may communicatewith the AMF 135 via the N2 interface and with the UPF+PGW-U 155 via theN3 interface. As another example, a base unit 110 may communicate withthe MIME 145 via the S1-MME interface and with the SGW via the S1-Uinterface. Other network interfaces are depicted, including, but notlimited to, a N4 interface between the UPF+PGW-U 155 and the SMF+PGW-C160, a N7 interface between the SMF+PGW-C 160 and the PCF+PCRF 165, a N8interface between the AMF 135 and the HSS+UDM 170, a N10 interfacebetween the SMF+PGW-C 160 and the HSS+UDM 170, a N11 interface betweenthe AMF 135 and the SMF+PGW-C 160, a N15 interface between the AMF 135and the PCF+PCRF 165, a S5-U interface between the SGW 150 and theUPF+PGW-U 155, a S5-C interface between the SGW 150 and the SMF+PGW-C160, a S6a interface between the MME 145 and the HSS+UDM 170, and theS11 interface between the MME 145 and the SGW 150.

Although not depicted, the wireless communication system 100 may supporta N1 interface between the remote unit 105 and the AMF 135. Note,however, that there is no network interface between the AMF 135 and theMME 145 (i.e., no N26 interface). This is because the AMF 135 and theMME 145 are not communicatively coupled. Accordingly, inter-systemhandover from the 5GC to EPC (or vice versa) is not supported.

In various embodiments, the remote unit 105 may register with a firstcommunication system and indicate (e.g., announce) one or more radiocapabilities to the first communication system. Here, the radiocapabilities relate to RAT. The remote unit 105 later determines toregister with a second communication system and updates the one or moreUE radio capabilities using a NAS procedure. Here, the first and secondcommunication systems may belong to the same PLMN. In one embodiment,the first communication system includes an EPC and wherein the secondcommunication system comprises a 5GC.

In certain embodiments, the remote unit 105 may perform a radiocapability exchange towards a base unit 110 (e.g., a RAN node). Here,the remote unit 105 updates one or more RAT capabilities of the secondcommunication system during the radio capability exchange.

If the remote unit 105's NG-RAN UE Radio Capability information changeswhile in CM-IDLE state, the remote unit 105 performs the Registrationprocedure with the Registration type set to Mobility Registration Updateindicating “UE Radio Capability Update”. When the AMF receivesRegistration Update Request with “UE Radio Capability Update”, it shalldelete any UE Radio Capability information that it has stored for theremote unit 105.

If the trigger to change the remote unit 105's NG-RAN UE RadioCapability information happens when the UE is in CM-CONNECTED state, theremote unit 105 first enters CM-IDLE state and then perform theRegistration procedure with the Registration type set to MobilityRegistration Update indicating “UE Radio Capability Update”.

To update the one or more UE radio capabilities, the remote unit 105transitions to a UE idle state, such as the CM-IDLE state. Note that thetransition of the “UE state” is in both the remote unit 105 and in thenetwork. As described in further detail herein, the transition may bebased on explicit signaling. Alternatively, this may be an implicittransition without signaling. and (within the remote unit 105) a NASentity (e.g., in the NAS layer) instructs an Access Stratum (“AS”)entity (e.g., in the AS layer) to modify an AS layer capability. In oneembodiment, modifying the AS layer capability comprises disabling aradio capability for a particular radio access technology. In anotherembodiment, modifying the AS layer capability comprises enabling a radiocapability for a particular radio access technology. In certainembodiments, when entering the CM Idle state, the remote unit 105 maydeactivate a radio resource control (“RRC”) idle state, e.g., using NASsignaling and/or RRC signaling. This is an instruction from the NASlayer to the AS layer to transition to RRC idle state. As such, the NASentity in the remote unit 105 may instruct the AS entity to discard (ordeactivate) the existing AS context and to modify an AS layer capabilityfor the remote unit 105.

In some embodiments, the remote unit 105 updates the one or more UEradio capabilities by having a NAS layer entity initiate a NAS updateprocedure. One suitable NAS update is the EPS NAS tracking area updateprocedure. Alternatively, the remote unit 105 may initiate the NASupdate procedure by sending a 5GS NAS registration request for mobilityupdate.

In other embodiments, a remote unit 105 may register with a firstcommunication system via a radio access network (“RAN”) node, announceradio capabilities for at least one RAT to the first communicationsystem, and detect a need to change an AS capability of the UE. Inresponse, the remote unit 105 may send a request to the network that aparticular AS capability be deprecated or disclaimed. Here, the requestmay be via NAS signaling or RRC signaling. Upon receiving the indicationof a deprecated/disclaimed capability (e.g., AS capability), the RANnode (e.g., base unit 110) does not consider the deprecated AScapability (e.g., considers the remote unit 105 to not have theparticular AS capability).

In certain embodiments, requesting that a particular AS capability bedeprecated (disclaimed) includes the remote unit 105 indicating that apreviously indicated (claimed) RAT capability is deprecated(disclaimed). In certain embodiments, the request that a particular AScapability be deprecated includes an indication that the network doesnot need to update the UE radio capability. In response to thedepreciation indication (disclaiming a RAT capability), the base unit110 (e.g., RAN node) no longer considers the deprecated capability(e.g., considers the remote unit 105 to not have the previouslyindicated RAT capability).

In one embodiment, detecting the need to change the AS capability of theUE comprises determining to register with a second communication system.In other embodiments, other trigger events may require the change in AScapability. Additionally, the remote unit 105 may later send a requestto the network to abolish the deprecated AS capability.

FIG. 2 depicts a network architecture 200 used for suspending servicesin a first core network while attached to a second core network,according to embodiments of the disclosure. The network architecture 200may be a simplified embodiment of the wireless communication system 100.As depicted, the network architecture 200 includes a UE 205 thatcommunicates with a 5GC 210 and with an EPC 215 via a RAN 220. The UE205 may be one embodiment of the remote unit 105, the 5GC 210 may be anembodiment of the first core network 130, and the EPC 215 may be anembodiment of the second core network 140. Additionally, the networkarchitecture 200 includes multiple core interworking functions 240, suchas a SMF/PGW-C interworking function, a UPF/PGW-U interworkingfunctions, etc. Although shared by the 5GC 210 and the EPC 215, theHSS+UDM is depicted as separate from the core interworking functions240.

In the depicted embodiment, the 5GC 210 and EPC 215 belong to the samePLMN. In various embodiments, the RAN 220 broadcasts an indication inthe system information (e.g., System Information Block (“SIB”)) that thePLMN supports DR-mode. Here, the UE 205 is configured to operate inDR-mode.

FIG. 2 shows an example of how a UE 205 may operate in DR mode, i.e.,registered to EPS and 5GC simultaneously. The UE 205 may establish PDNConnections in EPS and PDU sessions in 5GS. However, some PDN connectionin EPS may not support interworking with 5GS, for example EPS-exclusiveconnections 265 having the S/PGW 250 as the anchor point in the userplane. Accordingly, such a PDN connection cannot be transferred to 5GS.Similarly, some PDU Sessions in 5GS may not support interworking withEPS, for example 5GS-exclusive connections 270 having the UPF 245 as theanchor point in the user plane. Accordingly, such a PDU session cannotbe transferred to EPS. Yet another type of PDN connections or PDUsession can support interworking between EPS and 5GS, depicted asinterworking connections 275, because the anchor point in the controlplane (e.g., SMF+PGW-C) for the PDN connection or PDU session is acommon entity (e.g., one of the core interworking functions 240) and theanchor point in the user plane (e.g., UPF+PGW-U) is also a commonentity.

A UE 205 is expected to be able to enable (and disable) capabilities toaccess 5GS (e.g., 5GC 210). However, at the time of invention there isno access stratum procedure available to accomplish a change of UEcapabilities. Thus, the UE 205 may rely on upper layer (e.g., NAS)procedures to accomplish such a change. One example of a NAS procedureis the Detach/Re-attach procedure. Note that the UE 205 NAS capabilityis used in the mobility management entity (e.g., MME 235 or AMF 230) toselect a combined PGW-C+SMF entity (e.g., core interworking function240) in case of the UE 205 supporting both 5GC NAS and EPC NAS. The UE205 NAS capability is distinct from the UE 205 radio capability; thus,it should be differentiated between UE 205 NAS capability announcementand the UE 205 radio capability announcement.

DR mode is intended for interworking between EPS/E-UTRAN and 5GS/NR. Aproblem occurs when a UE 205 operating in DR mode goes out of 5GS/NRcoverage and enters an E-UTRA cell providing access to both EPC 215 and5GC 210. The UE 205 would end-up in 1) using the same cell to connect totwo different CNs (e.g., EPC 215 and 5GC 210) and 2) having two RRCconnections to the same eNB, whereas the one RRC connection is for EPC215 and the other one to 5GC 210.

In order to avoid such scenario, the UE 205 operating in DR mode is notto send its E-UTRA capability to NG-RAN when connected to 5GS/NR toavoid being handed over to 5GC-connected E-UTRA (e.g., RAN 220). Thisprevents the UE 205 from being connected to E-UTRAN/EPC 215 andE-UTRA/5GC 210 simultaneously using separate RRC connections via asingle RAN node (in the RAN 220) as a result of handover. However, 3GPPRelease 15 (“Rel-15”) leaves unclear which capability the UE 205 is toannounce when attaching to the EPS/E-UTRAN. Additionally, it is unclearwhether the UE 205 is to send to the CN its NAS capabilities (5GC NASand/or EPC NAS capabilities) when disabling/enabling in the AS layer aparticular RAT radio capability. Accordingly, current standards do notspecify whether the UE 205 sends its New Radio (“NR”) capability to theEPS/E-UTRAN when operating in DR mode.

In various embodiments, the UE 205 operating in DR mode is not to sendits E-UTRA capability to NG-RAN when connected to 5GS/NR in order toavoid being handed over to 5GC-connected E-UTRA. However, Rel-15 doesnot provide details about the UE 205 behavior while attached/registeredto the EPS. In order to avoid the configuration on Dual Connectivity(“DC”) with NR when the UE 205 is connected to E-UTRA/EPS and thesimultaneous use of RRC connection in NR/5GC, in one embodiment, the UE205 does not send its NR capability to E-UTRA when connected toEPS/E-UTRA to avoid being configured in EN-DC mode while also using NRfor accessing 5GS/NR.

If the UE 205 has been operating in DR mode and the UE 205 deregistersfrom one system, e.g., the UE 205 deregisters from the 5GS (thisderegistration may be implicit deregistration due to lack of coverage)and the UE 205 changes to Scheduling Request (“SR”) mode with EPS only,then the UE 205 may update its radio capability (e.g., to increase radiocapability by including the NR capability) to the other system where theUE 205 continues to be registered (e.g., in the EPS).

Note that by increasing the radio capability, the already selected corenetwork for existing PDU Sessions or PDN Connections may need to bereselected. For example, if the UE 205 is registered to EPS/E-UTRAN and5GS/NR and the UE 205 a) has not indicated NR capability to E-UTRAN andb) has not indicated E-UTRA capability to NR, the corresponding corenetwork node (e.g., MME 235) may have selected user plane nodes (e.g.,SGW or UPF) which do not support Dual Connectivity. Accordingly, afterincreasing the capability, e.g., after the UE 205 indicates DualConnectivity support with multiple RATs, the core network (e.g., MME235) may need to reselect another user plane node.

When considering UE capabilities, it should be differentiated betweenNAS layer capabilities and AS layer capabilities. For example, on theNAS layer the UE 205 may be capable of DR mode, may be 5GC NAS capableand/or EPC NAS capable, the UE 205 may support user plane (“UP”) and/orcontrol plane (“CP”) Consumer Internet-of-Things (“CIoT”) optimizationsor Narrowband Internet-of-Things (“NB-IoT”) capability, to mention justsome of the NAS layer capabilities. Additionally, on the AS layer, theUE 205 may support different RATs (e.g., UTRAN capable, E-UTRAN capableand/or NR capable) or different frequency bands and other features.

The UE 205 needs to differentiate between the following use cases fordisabling/enabling 4G or 5G capability:

Use Case A: If the UE 205 disables 5G capability in order to stayattached with EPS only due to e.g., use of feature(s) non-supported in5GS (e.g., ProSe, Multimedia Broadcast Multicast Services (“MBMS”), CIoToptimizations, Vehicle-to-Everything (“V2X”), etc.) but also other usecases can be possible, then the UE 205 does not indicate 5GC NAS to theEPC (e.g., MME 235) during NAS (e.g., TAU/Attach) procedure and the UE205 disables the NR capability in the AS layer. With other words,“disabling 5G capability” means disabling the 5GC NAS capability and theAS capability (e.g., NR capability).

Similarly, if the UE 205 enables the 5G capability, then the UE 205indicate 5GC NAS support to the EPC (e.g., MME 235) during NAS (e.g.,TAU/Attach) procedure and the UE 205 enables the NR capability in the ASlayer.

Please note that before disabling the 5G capability internally in the UE205, in order to assure clean state(s) in the network functions in 5GSand avoid unnecessary paging or other signaling, the UE 205 mayderegister in the 5GS. For example, the UE 205 sends a DeregistrationRequest message indicating an appropriate cause, e.g., moving to othersystem. If explicit deregistration is performed and after the UE 205receives the Deregistration Accept message, the UE 205 transfers toRM-Deregistered state in 5GS and the NAS layer may trigger the AS layerto disable the NR capability and the NAS layer itself disables the 5GCNAS support. The deregistration may be also implicit.

Use Case B: If the UE 205 disables 5G capability due to e.g., use of DRmode (but also other use cases can be possible), then the UE 205indicates 5GC NAS support to the EPC (e.g., MME 235) but disables onlythe NR capability in the AS layer. Therefore, in case of change betweenDR mode and SR mode, the talk is about AS capability change (e.g., RATcapability) and not of 5G capability change.

Similarly, if the UE 205 enables the 5G capability due to use of DRmode, the UE 205 indicates 5GC NAS support to the EPC (e.g., MME 235)during NAS (e.g., TAU/Attach) procedure and the UE 205 enables the NRcapability in the AS layer.

When the DR-capable UE 205 is initially registered with the 5GC 210 andthen discovers LTE coverage, the following steps may be taken. Note thatin general the UE 205 first registers with a single system e.g., the UE205 performs initial registration to 5GC in a PLMN (see messaging 255).Thus, the UE 205 would initially operate in a single registration modeand can announce its radio capability for multiple RATs (e.g., capableof NR and LTE). At some point of time the UE 205 determines to performDR mode.

When the DR-capable UE 205 is initially registered with the EPC 215 andthen discovers NR coverage, the following steps may be taken. Note thatin general the UE 205 first registers with a single system e.g., the UE205 performs initial attach to EPC 215 in a PLMN (see messaging 260).Thus, the UE 205 would initially operate in a single registration modeand can announce its radio capability for multiple RATs (e.g., capableof NR and LTE). At some point of time the UE 205 determines to performDR mode.

In various embodiments, when registering with the EPC 215, the UE 205indicates its capabilities, e.g., 5G NAS capable, support of “handover”for PDN connectivity, etc. Because the UE 205 intends to only use EPScurrently (e.g., no NR coverage), the UE 205 indicate its E-UTRAN and NRcapabilities to the LTE. The EPS/E-UTRAN may decide to configure DualConnectivity with NR, if NR cell is available. The MME 235 indicates tothe UE 205 that interworking with 5GS is supporting without N26.

While attached to the EPC 215, the UE 205 may discover NR coverage anddecide to perform DR mode, i.e., to register with 5GS. Per Rel-15, a UE205 wanting to use one or more EPS functionalities not supported by 5GSystem (e.g., ProSe, MBMS, CIOT optimizations, V2X, etc.), may disableall the related radio capabilities that allow the UE 205 to access 5GSystem when in CM-IDLE. Thus, radio capability change may be performedin CM/EMM Idle state, e.g., in order to prevent abrupt termination ofservices (disruption if active bearers) in CM/EMM Connected state.

Accordingly, the UE 205 may transition to CM/EMM Idle state to modifyits radio capabilities in the EPS. In various embodiments, the UE 205detects internally based on implementation, configuration (e.g.,initiation of DR mode, termination of DR mode, 5GS non-supported featureuse, etc.) that radio capability change should be performed in a firstregistered system. The UE 205 first enters CM/EMM Idle state before theNAS layer requests the AS layer to reconfigure the radio capabilities(e.g., increase or decrease radio capabilities). Afterwards the UE 205performs NAS layer signaling to 1) to request update for the UEcapability update (e.g., in 5GS or EPS) and 2) to change theregistration in the corresponding system. If the UE 205 is in CM/EMMConnected and RRC Inactive state for long time, the UE 205 may requestthe deactivation of the RRC Inactive state (or requesting Idle state dueto capability change/modification) using the NAS protocol or the RRCprotocol.

For initiating 5GS to EPS dual registration operation: if the UE 205 isaware that the network supports 5GS-EPS interworking without N26 and theUE 205 is dual registration capable and is already registered with the5GS, when the UE 205 determines to attach to a second system (e.g., EPS)in dual registration mode, the UE 205 performs the following procedures:

a. If the UE 205 is in connection management (CM) CONNECTED state in thefirst system, the UE 205 may indicate to the CN of the first system thatcapability change (e.g., reduce radio capabilities by excluding theradio capabilities of the RAT of a second system) is required. Thisindication may be performed via NAS layer signaling.

b. The 5GS (e.g., AMF 230) may disable RRC Inactive state in the NG-RAN.

c. The UE 205 enters CM IDLE state.

d. The NAS layer of the UE 205 indicates to the AS layer to disable theLTE capability when using NR.

e. The NAS layer of the UE 205 initiates registration update proceduretowards AMF 230 to update its capabilities. The UE 205 indicates reducedcapability to the NG-RAN (e.g., NR) node.

f. The UE 205 initiates NAS attach procedure with a second system (EPS)for DR mode.

For initiating EPS to 5GS dual registration operation: if the UE 205 isaware that the network supports EPS-5GS interworking without N26 and theUE 205 is dual registration capable and is already registered with theEPS, when the UE 205 determines to attach to a second system (e.g., 5GS)in dual registration mode, the UE 205 performs the following procedures:

a. If the UE 205 is in connection management (CM) CONNECTED state in thefirst system, the UE 205 may indicate to the CN of the first system thatcapability change (e.g., reduce radio capabilities by excluding theradio capabilities of the RAT of a second system) is required. Thisindication may be performed via NAS layer signaling.

b. The EPS (e.g., MME 235) may disable RRC Inactive state in theLTE-RAN.

c. The UE 205 enters CM IDLE state.

d. The NAS layer of the UE 205 indicates to the AS layer to disable theNR capability when using LTE.

e. The NAS layer of the UE 205 initiates registration update proceduretowards MME 235 to update its capabilities. The UE 205 indicates reducedcapability to the LTE-RAN node.

f. The UE 205 initiates NAS register procedure with a second system(5GS) for DR mode.

FIGS. 3A-3B depict a first procedure 300 for radio capability change ofa UE 205, according to embodiments of the disclosure. The firstprocedure 300 involves the UE 205, an NR RAN 305, an LTE RAN 310, theAMF 230, the MME 235, a SMF+PGW-C 160, and the HSS+UDM 225. The stepsshown in FIGS. 3A-3B are as described follows:

The procedure 300 begins at FIG. 3A. In step 0: The UE 205 is registeredin 5GS (see messaging 315). The UE 205 has indicated support of 1)NR+LTE radio capability to the NG-RAN node and 2) EPS NAS capability tothe AMF 230. In certain embodiments, the 5GS may configure DualConnectivity. The 5GS indicates to the UE 205 the interworking withoutN26 is supported.

Step 1: The UE 205 detects LTE coverage and determines to initiate dualregistration mode of operation. The UE 205 decides to change radiocapabilities in the currently used system, e.g., in the 5GS/NR (seeblock 320). The UE 205 also determines that it is in CM Connected stateand either in RRC Connected or RRC Inactive state (see block 325).

Step 2: If the UE 205 is in CM/EMM Connected state, the UE 205 maydetermine to initiate transition to CM Idle state. For this purpose, theUE 205 may perform one of the following actions:

The UE 205 NAS layer may query the RRC layer about the RRC state (i.e.,RRC Connected or RRC Inactive state). If the RRC state is RRC Inactive,the UE 205 may send a NAS indication to the AMF 230 to requestdisablement of the RRC Inactive state. For example, the UE 205 can senda Registration Request message having a type of Mobility RegistrationUpdate with indication ‘transfer to Idle state’ or ‘disable RRC Inactivestate’ or a similar indication). In addition, the UE 205 may indicatethe reason for transition to Idle state, e.g., UE 205 needs to change ASlayer capabilities.

The UE 205 may send NAS Deregistration Request message to the AMF 230with an indication that the Deregistration is due to UE 205 radiocapability change and an indication that re-registration is (e.g., soon)expected (see messaging 330). In such case, the AMF 230 may initiate aderegistration procedure, for example the deregistration proceduredescribed in 3GPP TS 23.502 version 15.1.0. At the end of thederegistration procedure, the UE 205 state in the AMF 230 isRM-Deregistered. The AMF 230 may however keep the security contextdownloaded previously from the UDM/UDR because the AMF 230 may expectre-registration soon.

The UE 205 may send an RRC message to the NG-RAN node (e.g., gNB) toindicate to disable the RRC Inactive state (see messaging 330). For thispurpose, the UE 205 may perform the RRC resume procedure with anindication to disable RRC Inactive state.

Step 3: AMF 230 to NR RAN 305: The AMF 230 initiates N2 procedure fordisabling the RRC Inactive state, if the RRC state is RRC Inactive (seemessaging 335). An existing N2 message or a new N2 message can be usedto request the NG-RAN node to disable the RRC Inactive state. If the AMF230 is not aware about the RRC state, the AMF 230 may request the RANnode to release the UE context of the UE 205.

Optionally, the AMF 230 may include an indication that the release isnot urgent and can be performed upon UE Inactivity. For example, the AMF230 may use N2 UE Context Release Request (release cause value, delaytolerant release), where the cause value may indicate the reason forreleasing the UE context, e.g., UE radio capability change. The ‘delaytolerant release’ indicates to the RAN node that the RRC connection canbe release upon UE Inactivity (e.g., short inactivity of 5 seconds or 10seconds), so that the release is not urgent.

Step 4: The NG-RAN node performs procedure for RRC Idle statetransition, e.g., after Inactivity timer expires (see messaging 340).

Step 5: UE 205 in CM/EMM Idle or RM Deregistered state: the NAS layerperforms AS layer modification (see block 345). For example, the ASlayer may increase or decrease radio capabilities, e.g., by including orexcluding a RAT capability.

The procedure 300 continues at FIG. 3B. In step 6 a, UE 205 to CN (e.g.,AMF 230): (Note, the UE 205 may be in CM/EMM Idle state) UE 205initiates NAS procedure (e.g., Registration procedure) to indicatechange of its radio capabilities (e.g., to reduce radio capabilities byexcluding the radio capabilities of a RAT or to increase the radiocapabilities) (see messaging 350). The UE 205 may use RegistrationRequest message having a type of Mobility Registration Update andincluding an indication that radio capability change is required. Thisindication can be called e.g., ‘UE 205 radio capability’ or ‘UE 205radio capability change’ or any other similar parameter name can beused. This ‘UE 205 radio capability change’ indication causes at the AMF230 to perform the steps 6 b and/or 6 c. The AMF 230 may reply to the UE205 with Registration Accept message including an appropriate causevalue of accepting or rejecting the requested radio capability change.

In step 6 b: The AMF 230 deletes the already stored UE 205 radiocapabilities received previously from the NG-RAN node (see block 355).

In step 6 c: The AMF 230 initiates N2 procedure to inform the RAN nodethat the AS capabilities are changed (see messaging 360). The AMF 230does not include already stored UE 205 radio capabilities. The AMF 230may send UE 205 context to the RAN node, so that the RAN node can knowthat the AS capabilities are changed.

In step 6 d: The NG-RAN node initiates RRC procedure to query the UE 205radio capabilities (see messaging 365). The UE 205 announces/sends itsradio capabilities by excluding the E-UTRA capabilities, since the ASlayer has been instructed so by the NAS layer.

If the UE 205 is in CM/EMM Connected state and the RRC Inactive state(please note that the AMF 230 may be aware about the activation of RRCInactive state if the AMF 230 has subscribed to RRC state notificationas described in TS 23.502 clause 4.8.3 “N2 Notification procedure”) andthe indication ‘UE 205 radio capability change’ is included, the AMF 230may decide first to disable the RRC Inactive state.

If the UE 205 is in RM-Deregistered state, the UE 205 does not need toinclude ‘UE 205 radio capability’ indication, as the AMF 230 would havealready deleted the previously stored UE 205 radio capabilities. The UE205 performs normal Registration procedure with type Initialregistration.

Step 7: The UE 205 initiates Attach procedure in the EPC/E-UTRAN system(see block 370).

Step 8: If the UE 205 is registered to another system (e.g., using DRmode and already registered to 5GS), the UE 205 announces (or sends) itsAS layer capability (i.e., the E-UTRA capability) to the eNB, but the UE205 excludes the NR radio capability (see messaging 375).

Note that steps 2-4 (grouped in the dotted line box (A)) show onesolution option for explicit UE-initiated signaling for disabling theRRC Inactive state or for transition to CM Idle state. Another option isto integrate the RRC Inactive state disablement procedure in theRegistration procedure for UE capability change, e.g., as shown in step6. Also, note that FIG. 4 shows an example signaling flow for the casewhere the UE 205 is registered first to the 5GS and the UE 205 attemptsa DR mode operation with EPS later.

For initiating EPS to 5GS dual registration case: analogically to theabove, just exchanging the EPS and 5GS. In other embodiments, similarsignaling flow is also applicable in the scenario where the UE 205 isfirst attached in the EPS and the UE 205 attempts a DR mode operationwith 5GS. In such case, the UE 205 would first need to decrease itsradio capabilities in the EPS, i.e., to disable the NR capability, andthen the UE 205 attempts Registration procedure to the 5GS via NR. Insuch embodiments, UE 205 perform at least steps 2 and/or 5 towards theEPS (e.g., eNB and/or MME 235) to request Idle state or disable the RRCInactive state in the E-UTRAN.

FIG. 4 shows a second procedure 400 for radio capability change of a UE205, according to embodiments of the disclosure. The second procedure400 involves the UE 205, an NR RAN 305, an LTE RAN 310, the AMF 230, theMME 235, a SMF+PGW-C 160, and the HSS+UDM 225. The steps shown in FIG. 4are as described follows:

The UE 205 sends a request to the network (e.g., an indication in NASmessage to the mobility serving node (e.g., MME 235 or AMF 230)) that aparticular AS capability (e.g., RAT capability) should not be considered(i.e., the RAT capability is deprecated/disclaimed). In such case UE 205radio capability is decreased without sending the full radio capabilityto the network. In similar way, the UE 205 can at any time endorse theuse of the deprecated RAT capability, i.e., the UE 205 can increase itscapability without sending the full radio capability, but insteadabolishing/canceling previously deprecated capability. This solution maybe applicable to any of the UE 205 states, e.g., CM/EMM Connected orCM/EMM Idle.

For example, the UE 205, which is attached to EPS and having announcesE-UTRA and NR capability to the E-UTRAN, indicates in NAS signaling tothe MME 235 that the NR shall not be considered for dual connectivity.The UE 205 may trigger such signaling e.g., based on starting a DR-modeand registering with 5GS/NR. Then the MME 235 indicates to the RAN node(e.g., eNB) that dual connectivity with NR shall not be configured. Uponthe signaling from the MME 235, the eNB learns that UE 205's radiocapability has not changed, but the eNB shall not consider configuringthe DC with NR for this UE 205.

If the UE 205 changes from DR mode to SR mode and stays attached to afirst system (e.g., EPS) or other trigger events for increasing theradio capability occur, the UE 205 sends an indication in NAS signalingto the MME 235 that the deprecated RAT capability (e.g., NR capability)may be endorsed, i.e., the deprecated RAT capability can be consideredfor dual connectivity. With other words, the NAS signaling ‘activates’ adeprecated RAT (e.g., NR) capability.

Step 0: The UE 205 is registered in 5GS (see messaging 405). The UE 205has indicated support of 1) NR+LTE radio capability to the NG-RAN nodeand 2) EPS NAS capability to the AMF 230. 5GS can configure dualconnectivity (DC). The 5GS indicates to the UE 205 the interworkingwithout N26 is supported.

Step 1: The UE 205 detects LTE coverage and determines to initiate dualregistration mode of operation (see block 410). The UE 205 decides tochange radio capabilities in the currently used system, e.g., in the5GS/NR. The UE 205 may determine that it is in CM Connected state andRRC Inactive state.

Step 2: The UE 205 initiates NAS procedure towards the core network(e.g., AMF 230) indicating that a particular AS capability (e.g., RATcapability) is deprecated (see messaging 415). With other words this RATcapability should not be considered for dual connectivity (DC)configuration. For example, the UE 205 may send a Registration Requestmessage including an indication that the E-UTRA capability should not beconsidered in the system.

Step 3 a: From CN to RAN: (if the UE 205 is in CM/EMM Connected state),the AMF 230 initiates UE 205 Context updated procedure towards theNG-RAN node to indicate that a particular UE 205 radio capability isdeprecated (see messaging 420). For example, the AMF 230 indicates tothe NG-RAN node that the NR capability is deprecated, i.e., dualconnectivity with E-UTRAN should not be configured.

Step 3 b: After the RAN node acknowledges the reception (and possiblyprocessing of the requested to deprecate RAT capability) (see messaging425). The Core network (e.g., the AMF 230) may respond to theregistration request of step 2 by sending an appropriate cause valuewhether the request from step 2 is accepted or rejected.

Step 4: The NG-RAN node performs RRC reconfiguration to disable the UE205 radio measurements in the indicated RAT (e.g., in the E-UTRA) (Seemessaging 430).

Step 5: The UE 205 initiates Attach procedure in the EPC/E-UTRAN system(see block 435).

Step 6: The UE 205 announces E-UTRA capability to the eNB, but the UE205 excludes the NR radio capability (see block 440).

In summary, the FIG. 5 shows a method for deprecating a particular AScapability, e.g., using NAS signaling, without the need to send thecomplete UE 205 radio capabilities to the network (e.g., to the RANnode). Please note that FIG. 5 shows an example signaling flow for thecase where the UE 205 is registered first to the 5GS and the UE 205attempts a DR mode operation with EPS later.

In another embodiment, it is also possible that the UE 205 abolishes thedeprecated AS capability at some point, i.e., the UE 205 enables (orendorses) the deprecated AS capability. For example, the UE 205 sends aNAS message (e.g., Registration Request message or TAU request message)including an indication that a deprecated AS capability (e.g.,deprecated RAT capability) should be enabled. Then the core network(e.g., MME 235 or AMF 230) updates the RAN node via S1 or N2 interfacewith an indication to enable the deprecated AS capability. The RAN nodecan perform RRC reconfiguration to configure the UE 205 to reportmeasurements for previously deprecated RAT.

In another embodiment related to the FIG. 4 , similar signaling flow isalso applicable in the scenario where the UE 205 is first attached inthe EPS and the UE 205 attempts a DR mode operation with 5GS. In suchcase, the UE 205 would first deprecate particular AS capabilities in theEPS, i.e., to disable the NR capability, and then the UE 205 attemptsRegistration procedure to the 5GS via NR.

In yet another embodiment related to the FIG. 4 , the network maydetermine to deprecate a particular AS capability (e.g., RAT capability)without explicit indication by the UE 205. For example, this can beperformed including signaling exchange via HSS+UDM 225. When a UE 205registered to 5GS decides to use DR mode and attempts to attach to theEPS (e.g., MME 235), the MME 235 updates the HSS+UDM 225 indicating thatthe UE 205 is attaching for DR mode of operation. The HSS+UDM 225informs the AMF 230 that the UE 205 is now in addition attached to theEPS. Then the AMF 230 initiates signaling towards the RAN node (e.g.,gNB) to indicate that the E-UTRA capability is deprecated. The AMF 230assumes that the UE 205 has sent E-UTRA capability to gNB because theE-UTRA is a native RAT in NG-RAN.

In certain embodiments, the UE 205 may determine to not send radiomeasurement reports to the RAN node including measurements from a RATwhich the UE 205 uses in another system. For example, if the UE 205 hasannounced NR capabilities to the E-UTRAN node and the UE 205 isconfigured to perform measurements of NR cell, and the UE 205 is in DRmode with the 5GC/NR, the UE 205 determines to not report radiomeasurements of NR cell even if the UE 205 can measure signal from NRcell. This can be done by either signaling some special or reservedvalues; that indicate to the network that the UE 205 is neithermeasuring NR cell nor is it interested in being handed over to NR cell;or, by not making any measurements at all. In any case, the UE 205 shallreport only especial or Zero signal level (Reference Signal ReceivedPower (“RSRP”), for example) if periodic reporting is configured. The UE205 may reject measurement gaps configured for such purposes.Alternatively, a UE 205 may directly indicate to the RAN network that itis not interested in measuring or being handed over to an NR cell, byway of a new RRC signaling just for example.

In certain embodiments, if the UE 205 is operating in DR mode, but theUE 205 is only attached/registered with the first system (e.g., 5GS)without established PDN connection or PDU Session, then the UE 205continues to use its dual radio capabilities, i.e., the UE 205 uses thefirst system radio capability (e.g., NR capabilities) to the secondsystem (e.g., EPS). Before the UE 205 initiates PDN connectionestablishment or PDU Session establishment in the first system, the UE205 performs radio capability update procedure in the second system inorder to exclude the radio capabilities of the first system (e.g.,exclude NR capability).

Please note that the use cases for triggering radio capability changecan be various. In some embodiments the assumption is the enablement ordisablement of DR mode, however other use cases are possible. Forexample, the modem capabilities (e.g., mobile equipment (ME) capability)changes due to hardware modification like attaching or detachinghardware to the terminal. Another example is that the user can enable ordisable terminal capability via the phone's menu.

FIG. 5 depicts a user equipment apparatus 500 that may be used for UEpower control for multiple UL carriers, according to embodiments of thedisclosure. The user equipment apparatus 500 may be one embodiment ofthe remote unit 105 and/or UE 205, described above. Furthermore, theuser equipment apparatus 500 may include a processor 505, a memory 510,an input device 515, an output device 520, a transceiver 525 forcommunicating with one or more base units 110.

As depicted, the transceiver 525 may include a transmitter 530 and areceiver 535. The transceiver 525 may also support one or more networkinterfaces 540, such as the Uu interface used to communicate with a gNB,or another suitable interface for communicating with a RAN (e.g., firstaccess network 120 and/or second access network 125). In someembodiments, the input device 515 and the output device 520 are combinedinto a single device, such as a touchscreen. In certain embodiments, theuser equipment apparatus 500 may not include any input device 515 and/oroutput device 520.

The processor 505, in one embodiment, may include any known controllercapable of executing computer-readable instructions and/or capable ofperforming logical operations. For example, the processor 505 may be amicrocontroller, a microprocessor, a central processing unit (“CPU”), agraphics processing unit (“GPU”), an auxiliary processing unit, a fieldprogrammable gate array (“FPGA”), or similar programmable controller. Insome embodiments, the processor 505 executes instructions stored in thememory 510 to perform the methods and routines described herein. Theprocessor 505 is communicatively coupled to the memory 510, the inputdevice 515, the output device 520, and the transceiver 525.

In various embodiments, the processor 505 registers with a firstcommunication system via the RAN node. In some embodiments, registeringwith the first communication system includes indicating one or more UEradio capabilities for at least one RAT to the first communicationsystem.

The processor 505 detects a trigger to perform radio capability changefor at least one radio access technology (“RAT”). In some embodiments,detecting a trigger to perform radio capability change includesdetermining to perform dual-registration with a second communicationsystem. In some embodiments, detecting a trigger to perform radiocapability change includes determining to register with a secondcommunication system, the second system different than the first system.In certain embodiments, the first and second communication systemsbelonging to the same PLMN. In certain embodiments, the firstcommunication system includes an EPC and wherein the secondcommunication system includes a 3GPP fifth generation core network.

The processor 505 transitions the UE state of the user equipmentapparatus 500 to an idle state. In various embodiments, transitioningthe UE state to an idle state includes entering a Connection Management(“CM”) Idle state on the NAS layer. In such embodiments, a NAS entityinstructs a UE Access Stratum (“AS”) entity to discard/deactivate theexisting AS context and instructs the UE AS entity to modify an AS layercapability for the user equipment apparatus 500 in response to enteringthe CM Idle state. In certain embodiments, modifying the AS layercapability includes disabling a UE capability for a particular radioaccess technology. In certain embodiments, modifying the AS layercapability includes enabling a UE capability for a particular radioaccess technology. In certain embodiments, entering the CM Idle stateincludes deactivating the AS context to enter a radio resource control(“RRC”) idle state using, e.g., NAS signaling and/or RRC signaling.

The processor 505 requests the network (e.g., the first communicationsystem) to update one or more UE radio capabilities while in the idlestate. In some embodiments, requesting to update one or more UE radiocapabilities includes performing a radio capability exchange towards theRAN node.

In various embodiments, requesting to update one or more UE radiocapabilities includes using a NAS signaling procedure to indicate theupdate of one or more UE radio capabilities. In one embodiment,requesting to update one or more UE radio capabilities includes sendinga NAS registration request. Here, the NAS registration has a mobilityregistration type and indicates the updated one or more UE radiocapabilities. In another embodiment, requesting to update one or more UEradio capabilities includes sending a tracking area update (“TAU”)request. Here, the TAU request indicates the updated one or more UEradio capabilities.

In some embodiments, detecting a trigger to perform radio capabilitychange includes detecting a need to change an Access Stratum (“AS”)capability of the user equipment apparatus 500. In such embodiments,requesting to update one or more UE radio capabilities includesrequesting that a particular AS capability be deprecated, wherein theRAN node does not consider the particular AS capability. In certainembodiments, requesting that a particular AS capability be deprecatedincludes sending one of a NAS message and an RRC message to a corenetwork.

In certain embodiments, requesting that a particular AS capability bedeprecated includes indicating that a previously indicated RATcapability is deprecated. In certain embodiments, requesting that aparticular AS capability be deprecated includes indicating that the corenetwork does not need to update the UE radio capability. In someembodiments, detecting the need to change the AS capability of the userequipment apparatus 500 includes determining to register with a secondcommunication system. In certain embodiments, the processor 505 furthersends a request to the network to abolish the deprecated AS capability.

The memory 510, in one embodiment, is a computer readable storagemedium. In some embodiments, the memory 510 includes volatile computerstorage media. For example, the memory 510 may include a RAM, includingdynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or staticRAM (“SRAM”). In some embodiments, the memory 510 includes non-volatilecomputer storage media. For example, the memory 510 may include a harddisk drive, a flash memory, or any other suitable non-volatile computerstorage device. In some embodiments, the memory 510 includes bothvolatile and non-volatile computer storage media.

In some embodiments, the memory 510 stores data related to modifying aradio capability. For example, the memory 510 may store radiocapabilities, registrations, and the like. In certain embodiments, thememory 510 also stores program code and related data, such as anoperating system or other controller algorithms operating on the remoteunit 105.

The input device 515, in one embodiment, may include any known computerinput device including a touch panel, a button, a keyboard, a stylus, amicrophone, or the like. In some embodiments, the input device 515 maybe integrated with the output device 520, for example, as a touchscreenor similar touch-sensitive display. In some embodiments, the inputdevice 515 includes a touchscreen such that text may be input using avirtual keyboard displayed on the touchscreen and/or by handwriting onthe touchscreen. In some embodiments, the input device 515 includes twoor more different devices, such as a keyboard and a touch panel.

The output device 520, in one embodiment, is designed to output visual,audible, and/or haptic signals. In some embodiments, the output device520 includes an electronically controllable display or display devicecapable of outputting visual data to a user. For example, the outputdevice 520 may include, but is not limited to, an Liquid Crystal Display(“LCD”), an Light-Emitting Diode (“LED”) display, an Organic LED(“OLED”) display, a projector, or similar display device capable ofoutputting images, text, or the like to a user. As another,non-limiting, example, the output device 520 may include a wearabledisplay separate from, but communicatively coupled to, the rest of theuser equipment apparatus 500, such as a smart watch, smart glasses, aheads-up display, or the like. Further, the output device 520 may be acomponent of a smart phone, a personal digital assistant, a television,a table computer, a notebook (laptop) computer, a personal computer, avehicle dashboard, or the like.

In certain embodiments, the output device 520 includes one or morespeakers for producing sound. For example, the output device 520 mayproduce an audible alert or notification (e.g., a beep or chime). Insome embodiments, the output device 520 includes one or more hapticdevices for producing vibrations, motion, or other haptic feedback. Insome embodiments, all or portions of the output device 520 may beintegrated with the input device 515. For example, the input device 515and output device 520 may form a touchscreen or similar touch-sensitivedisplay. In other embodiments, the output device 520 may be located nearthe input device 515.

The transceiver 525 includes at least transmitter 530 and at least onereceiver 535. One or more transmitters 530 may be used to provide ULcommunication signals to a base unit 110. Similarly, one or morereceivers 535 may be used to receive DL communication signals from thebase unit 110, as described herein. Although only one transmitter 530and one receiver 535 are illustrated, the user equipment apparatus 500may have any suitable number of transmitters 530 and receivers 535.Further, the transmitter(s) 530 and the receiver(s) 535 may be anysuitable type of transmitters and receivers. In one embodiment, thetransceiver 525 includes a first transmitter/receiver pair used tocommunicate with a mobile communication network over licensed radiospectrum and a second transmitter/receiver pair used to communicate witha mobile communication network over unlicensed radio spectrum.

As discussed above, the transceiver 525 communicates with one or morenetwork functions of a mobile communication network via one or moreaccess networks. The transceiver 525 operates under the control of theprocessor 505 to transmit messages, data, and other signals and also toreceive messages, data, and other signals. For example, the processor505 may selectively activate the transceiver (or portions thereof) atparticular times in order to send and receive messages. The transceiver525 may include one or more transmitters 530 and one or more receivers535. In certain embodiments, the one or more transmitters 530 and/or theone or more receivers 535 may share transceiver hardware and/orcircuitry. For example, the one or more transmitters 530 and/or the oneor more receivers 535 may share antenna(s), antenna tuner(s),amplifier(s), filter(s), oscillator(s), mixer(s),modulator/demodulator(s), power supply, and the like.

In various embodiments, the transceiver 525 is configured tocommunication with 3GPP access network(s) and/or non-3GPP accessnetwork(s). In some embodiments, the transceiver 525 implements modemfunctionality for the 3GPP access network(s) and/or the non-3GPP accessnetwork(s). In one embodiment, the transceiver 525 comprises a chip thatimplements multiple logical transceivers using different communicationprotocols or protocol stacks, while using common physical hardware. Forexample, the transceiver 525 may include one application-specificintegrated circuit (“ASIC”) which includes the function of firsttransceiver and second transceiver for accessing networks of differentRATs. In other embodiments, the transceiver 525 comprises separatetransceiver hardware for accessing networks of different RATs.

FIG. 6 is a schematic flow chart diagram illustrating one embodiment ofa method 600 for modifying a radio capability, according to embodimentsof the disclosure. In some embodiments, the method 600 is performed by aUE, such as the remote unit 105, the UE 205, and/or the user equipmentapparatus 500. In certain embodiments, the method 600 may be performedby a processor executing program code, for example, a microcontroller, amicroprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, orthe like.

The method 600 includes registering 605 with a first communicationsystem via a radio access network (“RAN”) node. In some embodiments,registering with the first communication system includes indicating oneor more UE radio capabilities for at least one RAT to the firstcommunication system.

The method 600 includes detecting 610 a trigger to perform radiocapability change for at least one radio access technology (“RAT”). Insome embodiments, detecting 610 a trigger to perform radio capabilitychange includes determining to register with a second communicationsystem, the second system different than the first system. In certainembodiments, the first and second communication systems belonging to thesame PLMN. In certain embodiments, the first communication systemincludes an EPC and wherein the second communication system includes a3GPP fifth generation core network.

The method 600 includes transitioning 615 the UE state to an idle state.In various embodiments, transitioning 615 the UE state to an idle stateincludes entering a Connection Management (“CM”) Idle state on the NASlayer entity of the UE. In certain embodiments, entering the CM Idlestate includes deactivating the AS context (e.g., using NAS signaling orRRC signaling) to enter an RRC idle state.

The method 600 includes sending 620 a request to the network to updateone or more UE radio capabilities while in the idle state. The method600 ends. In some embodiments, sending 620 the request to update one ormore UE radio capabilities includes using a NAS signaling procedure toindicate the update of one or more UE radio capabilities. In oneembodiment, sending 620 the request to update one or more UE radiocapabilities includes sending a NAS registration request, said requesthaving a mobility registration type and indicating the updated one ormore UE radio capabilities. In another embodiment, sending 620 therequest to update one or more UE radio capabilities includes sending atracking area update request, said request indicating the updated one ormore UE radio capabilities.

In certain embodiments, detecting 610 a trigger to perform radiocapability change includes determining to perform dual-registration witha second communication system. In such embodiments, sending 620 therequest to update one or more UE radio capabilities includes performinga radio capability exchange towards the RAN node.

In some embodiments, detecting 610 a trigger to perform radio capabilitychange includes detecting a need to change an Access Stratum (“AS”)capability of the UE, wherein sending 620 the request to update one ormore UE radio capabilities includes requesting that a particular AScapability be deprecated, wherein the RAN node does not consider theparticular AS capability. In certain embodiments, detecting the need tochange the AS capability of the UE includes determining to register witha second communication system.

In certain embodiments, requesting that a particular AS capability bedeprecated includes sending a NAS message or an RRC message to a corenetwork. In certain embodiments, requesting that a particular AScapability be deprecated includes indicating that a previously indicatedRAT capability is deprecated. In certain embodiments, requesting that aparticular AS capability be deprecated includes indicating that the corenetwork does not need to update the UE radio capability.

FIG. 7 is a schematic flow chart diagram illustrating one embodiment ofa method 700 for modifying a radio capability, according to embodimentsof the disclosure. In some embodiments, the method 700 is performed by aUE, such as the remote unit 105, the UE 205, and/or the user equipmentapparatus 500. In certain embodiments, the method 700 may be performedby a processor executing program code, for example, a microcontroller, amicroprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, orthe like.

The method 700 includes determining 705 that an update of a radio accesscapability for a first radio access technology is required based atleast in part on whether to use a second radio access technology. Themethod 700 includes switching 710 to an idle state based on determiningthat the update of the radio access capability for the first radioaccess technology is required. The method 700 includes transmitting 715a request message indicating that the update of the radio accesscapability for the first radio access technology is required in responseto switching to the idle state, the request message further indicatingto delete a stored radio access capability associated with the UE andobtain a new radio access capability associated with the UE. The method700 ends.

Disclosed herein is a first apparatus for modifying a radio capability.The first apparatus may be implemented by the remote unit 105, the UE205, and/or the user equipment apparatus 500. The first apparatusincludes a processor and a transceiver that communicates with a RANnode. The processor registers with a first communication system via theRAN node. The processor detects a trigger to perform radio capabilitychange for at least one radio access technology (“RAT”) and transitionsa UE state of the apparatus to an idle state. The processor furthersends a request to the first communication system to update one or moreUE radio capabilities while in the idle state.

In some embodiments, registering with the first communication systemincludes indicating one or more UE radio capabilities for at least oneRAT to the first communication system. In some embodiments, detecting atrigger to perform radio capability change includes determining toperform dual-registration with a second communication system. In suchembodiments, sending the request to update one or more UE radiocapabilities includes performing a radio capability exchange towards theRAN node, wherein the processor updates one or more UE radio accesstechnology capabilities of the second communication system during theradio capability exchange.

In various embodiments, sending the request to update one or more UEradio capabilities includes using a NAS signaling procedure to indicatethe update of one or more UE radio capabilities. In one embodiment,sending the request to update one or more UE radio capabilities includessending a NAS registration request. Here, the NAS registration has amobility registration type and indicates the updated one or more UEradio capabilities. In another embodiment, sending the request to updateone or more UE radio capabilities includes sending a tracking areaupdate (“TAU”) request. Here, the TAU request indicates the updated oneor more UE radio capabilities.

In some embodiments, detecting a trigger to perform radio capabilitychange includes determining to register with a second communicationsystem, the second system different than the first system. In certainembodiments, the first and second communication systems belonging to thesame PLMN. In certain embodiments, the first communication systemincludes an EPC and wherein the second communication system includes a3GPP fifth generation core network.

In various embodiments, transitioning the UE state to an idle stateincludes entering a Connection Management (“CM”) Idle state on the NASlayer. In such embodiments, the first apparatus includes a NAS entitythat instructs a UE Access Stratum (“AS”) entity to discard (ordeactivate) the existing AS context and instructs the UE AS entity tomodify an AS layer capability for the apparatus in response to enteringthe CM Idle state. In certain embodiments, modifying the AS layercapability includes disabling a UE capability for a particular radioaccess technology. In certain embodiments, modifying the AS layercapability includes enabling a UE capability for a particular radioaccess technology. In certain embodiments, entering the CM Idle stateincludes deactivating the AS context to enter a radio resource control(“RRC”) idle state using, e.g., NAS signaling and/or RRC signaling.

In some embodiments, detecting a trigger to perform radio capabilitychange includes detecting a need to change an Access Stratum (“AS”)capability of the apparatus. In such embodiments, sending the request toupdate one or more UE radio capabilities includes requesting that aparticular AS capability be deprecated, wherein the RAN node does notconsider the particular AS capability. In certain embodiments,requesting that a particular AS capability be deprecated includessending wither a NAS message or an RRC message to a core network.

In certain embodiments, requesting that a particular AS capability bedeprecated includes indicating that a previously indicated RATcapability is deprecated. In certain embodiments, requesting that aparticular AS capability be deprecated includes indicating that the corenetwork does not need to update the UE radio capability. In someembodiments, detecting the need to change the AS capability of theapparatus includes determining to register with a second communicationsystem. In certain embodiments, the processor further sends a request tothe network to abolish the deprecated AS capability.

Disclosed herein is a first method for modifying a radio capability. Thefirst method may be performed by a UE, such as the remote unit 105, theUE 205, and/or the user equipment apparatus 500. The first methodincludes registering with a first communication system via a radioaccess network (“RAN”) node and detecting a trigger to perform radiocapability change for at least one radio access technology (“RAT”). Thefirst method includes transitioning a UE state to an idle state andsending a request to the first communication system to update one ormore UE radio capabilities while in the idle state.

In some embodiments, registering with the first communication systemincludes indicating one or more UE radio capabilities for at least oneRAT to the first communication system. In certain embodiments, detectinga trigger to perform radio capability change includes determining toperform dual-registration with a second communication system. In suchembodiments, sending the request to update one or more UE radiocapabilities includes performing a radio capability exchange towards theRAN node. Here, the first method may also include updating one or moreUE radio access technology capabilities of the second communicationsystem during the radio capability exchange.

In some embodiments, sending the request to update one or more UE radiocapabilities includes using a NAS signaling procedure to indicate theupdate of one or more UE radio capabilities. In one embodiment, sendingthe request to update one or more UE radio capabilities includes sendinga NAS registration request, said request having a mobility registrationtype and indicating the updated one or more UE radio capabilities. Inanother embodiment, sending the request to update one or more UE radiocapabilities includes sending a tracking area update request, saidrequest indicating the updated one or more UE radio capabilities.

In some embodiments, detecting a trigger to perform radio capabilitychange includes determining to register with a second communicationsystem, the second system different than the first system. In certainembodiments, the first and second communication systems belonging to thesame PLMN. In certain embodiments, the first communication systemincludes an EPC and wherein the second communication system includes a3GPP 5GC.

In various embodiments, transitioning to an idle state includes enteringa Connection Management (“CM”) Idle state on the NAS layer of the UE. Insuch embodiments, the first method may include a NAS entity instructinga UE Access Stratum (“AS”) entity to discard/deactivate the existing AScontext and instructing the UE AS entity to modify an AS layercapability for the UE in response to entering the CM Idle state. Incertain embodiments, modifying the AS layer capability includesdisabling a UE capability for a particular radio access technology. Incertain embodiments, modifying the AS layer capability includes enablinga UE capability for a particular radio access technology. In certainembodiments, entering the CM Idle state includes deactivating the AScontext to enter a radio resource control (“RRC”) idle state using,e.g., NAS signaling and/or RRC signaling.

In some embodiments, detecting a trigger to perform radio capabilitychange includes detecting a need to change an Access Stratum (“AS”)capability of the UE, wherein sending the request to update one or moreUE radio capabilities includes requesting that a particular AScapability be deprecated, wherein the RAN node does not consider theparticular AS capability. In certain embodiments, detecting the need tochange the AS capability of the UE includes determining to register witha second communication system. Here, the first method may includesending a request to the network to abolish the deprecated AScapability.

In certain embodiments, requesting that a particular AS capability bedeprecated includes sending a NAS message or an RRC message to a corenetwork. In certain embodiments, requesting that a particular AScapability be deprecated includes indicating that a previously indicatedRAT capability is deprecated. In certain embodiments, requesting that aparticular AS capability be deprecated includes indicating that the corenetwork does not need to update the UE radio capability.

Disclosed herein is a first method for modifying a radio capability. Thefirst method may be performed by a UE, such as the remote unit 105, theUE 205, and/or the user equipment apparatus 500. The first methodincludes a memory and a processor coupled to the memory, the processorconfigured to cause the apparatus to: A) determine that an update of aradio access capability for a first radio access technology is requiredbased at least in part on whether to use a second radio accesstechnology; B) switch to an idle state based on the determination thatthe update of the radio access capability for the first radio accesstechnology is required; and C) transmit a request message indicatingthat the update of the radio access capability for the first radioaccess technology is required in response to the switch to the idlestate, the request message further indicating to delete a stored radioaccess capability associated with the apparatus and obtain a new radioaccess capability associated with the apparatus.

In some embodiments, to determine that the update of the radio accesscapability for the first radio access technology is required, theprocessor is configured to cause the apparatus to determine whether theapparatus is operating concurrently in accordance with the first radioaccess technology and the second radio access technology.

In some embodiments, to transmit the request message indicating that theupdate of the radio access capability for the first radio accesstechnology is required, the processor is configured to cause theapparatus to transmit the request message using a non-access stratumprocedure. In such embodiments, the request message includes anon-access stratum request message.

In some embodiments, to transmit the request message indicating that theupdate of the radio access capability for the first radio accesstechnology is required, the processor is configured to cause theapparatus to transmit a tracking area update request indicating that theupdate of the radio access capability for the first radio accesstechnology is required.

In some embodiments, the processor is configured to cause the apparatusto register with a first communication system using the first radioaccess technology. In certain embodiments, to determine that the updateof the radio access capability for the first radio access technology isrequired, the processor is configured to cause the apparatus todetermine whether the registered first communication system supports aservice for the apparatus.

In some embodiments, to determine that the update of the radio accesscapability for the first radio access technology is required, theprocessor is configured to cause the apparatus to detect a trigger thatthe update of the radio access capability for the first radio accesstechnology is required. In such embodiments, the trigger includes that aservice for the apparatus is unsupported by the registered firstcommunication system.

In certain embodiments, the processor is configured to cause theapparatus to register with a second communication system based on thedetermination that the update of the radio access capability for thefirst radio access technology is required. In further embodiments, thefirst communication system is different than the second communicationsystem.

In some embodiments, to register with the first communication system,the processor is configured to cause the apparatus to transmit anindication of one or more radio access capabilities associated with theapparatus.

Disclosed herein is a second method for modifying a radio capability.The second method may be performed by a UE, such as the remote unit 105,the UE 205, and/or the user equipment apparatus 500. The second methodincludes determining that an update of a radio access capability for afirst radio access technology is required based at least in part onwhether to use a second radio access technology. The second methodincludes switching to an idle state based on determining that the updateof the radio access capability for the first radio access technology isrequired and transmitting a request message indicating that the updateof the radio access capability for the first radio access technology isrequired in response to switching to the idle state, the request messagefurther indicating to delete a stored radio access capability associatedwith the UE and obtain a new radio access capability associated with theUE.

In some embodiments, determining that the update of the radio accesscapability for the first radio access technology is required includesdetermining whether the UE is operating concurrently in accordance withthe first radio access technology and the second radio accesstechnology.

In some embodiments, transmitting the request message indicating thatthe update of the radio access capability for the first radio accesstechnology is required includes transmitting the request message using anon-access stratum procedure. In such embodiments, the request messagemay include a non-access stratum request message.

In some embodiments, transmitting the request message indicating thatthe update of the radio access capability for the first radio accesstechnology is required includes transmitting a tracking area updaterequest indicating that the update of the radio access capability forthe first radio access technology is required.

In some embodiments, the second method further includes registering witha first communication system using the first radio access technology. Incertain embodiments, determining that the update of the radio accesscapability for the first radio access technology is required includesdetermining whether the registered first communication system supports aservice for the UE.

In some embodiments, determining that the update of the radio accesscapability for the first radio access technology is required includesdetecting a trigger that the update of the radio access capability forthe first radio access technology is required. In such embodiments, thetrigger includes that a service for the UE is unsupported by theregistered first communication system.

In certain embodiments, the second method further includes registeringwith a second communication system based on determining that the updateof the radio access capability for the first radio access technology isrequired. In further embodiments, the first communication system isdifferent than the second communication system.

In some embodiments, registering with the first communication systemincludes transmitting an indication of one or more radio accesscapabilities associated with the UE.

Embodiments may be practiced in other specific forms. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

1. An apparatus comprising: a memory; and a processor coupled to thememory, the processor configured to cause the apparatus to: determinethat an update of a radio access capability for a first radio accesstechnology is required based at least in part on whether to use a secondradio access technology; switch to an idle state based on thedetermination that the update of the radio access capability for thefirst radio access technology is required; and transmit a requestmessage indicating that the update of the radio access capability forthe first radio access technology is required in response to the switchto the idle state, the request message further indicating to delete astored radio access capability associated with the apparatus and obtaina new radio access capability associated with the apparatus.
 2. Theapparatus of claim 1, wherein, to determine that the update of the radioaccess capability for the first radio access technology is required, theprocessor is configured to cause the apparatus to: determine whether theapparatus is operating concurrently in accordance with the first radioaccess technology and the second radio access technology.
 3. Theapparatus of claim 1, wherein, to transmit the request messageindicating that the update of the radio access capability for the firstradio access technology is required, the processor is configured tocause the apparatus to: transmit the request message using a non-accessstratum procedure, wherein the request message comprises a non-accessstratum request message.
 4. The apparatus of claim 1, wherein, totransmit the request message indicating that the update of the radioaccess capability for the first radio access technology is required, theprocessor is configured to cause the apparatus to: transmit a trackingarea update request indicating that the update of the radio accesscapability for the first radio access technology is required.
 5. Theapparatus of claim 1, wherein the processor is configured to cause theapparatus to: register with a first communication system using the firstradio access technology.
 6. The apparatus of claim 5, wherein, todetermine that the update of the radio access capability for the firstradio access technology is required, the processor is configured tocause the apparatus to: determine whether the registered firstcommunication system supports a service for the apparatus.
 7. Theapparatus of claim 5, wherein the processor is configured to cause theapparatus to: detect a trigger that the update of the radio accesscapability for the first radio access technology is required, whereinthe trigger comprises that a service for the apparatus is unsupported bythe registered first communication system.
 8. The apparatus of claim 5,wherein the processor is configured to cause the apparatus to: registerwith a second communication system based on the determination that theupdate of the radio access capability for the first radio accesstechnology is required.
 9. The apparatus of claim 8, wherein the firstcommunication system is different than the second communication system.10. The apparatus of claim 5, wherein, to register with the firstcommunication system, the processor is configured to cause the apparatusto: transmit an indication of one or more radio access capabilitiesassociated with the apparatus.
 11. A method at a user equipment (“UE”),the method comprising: determining that an update of a radio accesscapability for a first radio access technology is required based atleast in part on whether to use a second radio access technology;switching to an idle state based on determining that the update of theradio access capability for the first radio access technology isrequired; and transmitting a request message indicating that the updateof the radio access capability for the first radio access technology isrequired in response to switching to the idle state, the request messagefurther indicating to delete a stored radio access capability associatedwith the UE and obtain a new radio access capability associated with theUE.
 12. The method of claim 11, wherein determining that the update ofthe radio access capability for the first radio access technology isrequired comprises: determining whether the UE is operating concurrentlyin accordance with the first radio access technology and the secondradio access technology.
 13. The method of claim 11, whereintransmitting the request message indicating that the update of the radioaccess capability for the first radio access technology is requiredcomprises: transmitting the request message using a non-access stratumprocedure, wherein the request message comprises a non-access stratumrequest message.
 14. The method of claim 11, wherein transmitting therequest message indicating that the update of the radio accesscapability for the first radio access technology is required comprises:transmitting a tracking area update request indicating that the updateof the radio access capability for the first radio access technology isrequired.
 15. The method of claim 11, further comprising: registeringwith a first communication system using the first radio accesstechnology.
 16. The method of claim 15, wherein determining that theupdate of the radio access capability for the first radio accesstechnology is required comprises: determining whether the registeredfirst communication system supports a service for the UE.
 17. The methodof claim 15, further comprising: detecting a trigger that the update ofthe radio access capability for the first radio access technology isrequired, wherein the trigger comprises that a service for the UE isunsupported by the registered first communication system.
 18. The methodof claim 15, further comprising: registering with a second communicationsystem based on determining that the update of the radio accesscapability for the first radio access technology is required.
 19. Themethod of claim 18, wherein the first communication system is differentthan the second communication system.
 20. The method of claim 15,wherein registering with the first communication system comprises:transmitting an indication of one or more radio access capabilitiesassociated with the UE.